Convex vector precoding is proposed for interference-free reception in single user MIMO channels using either spatial matched filtering or distributed antenna detection at the receiver. We use the replica method of statistical physics to compare the large system performance (in terms of transmitted energy vs. uncoded transmission rate) of both the matched filter and the distributed detection schemes. Using a convex quaternary alphabet we find that distributed detection is most advantageous only when the ratio of antennas at the receiver to that at the transmitter is either smaller than 0.5 or between 1 and 1.22. Matched filter detection is most advantageous for ratios greater than 2. In the two remaining regions the choice of precoding for matched filter or distributed detection results in a tradeoff between energy and transmission rate.